Secret ingredient for productive pastures

Published: 31 Aug 2018

Five Tasmanian dairy farms participated in a trial by the Tasmanian Institute of Agriculture (TIA) to determine the best way to include plantain (a forage herb) in traditional ryegrass pastures in an effort to boost productivity.

The trial was led by TIA Research Fellow Pieter Raedts and PhD candidate Adam Langworthy, and identified the optimal seeding rate per hectare for two different methods of adding plantain to an existing paddock.

“Plantain is a forage herb that could be described as ‘lollies for cows’ because it increases the palatability of pasture, encouraging cows to consume more which can lead to an increase in milk solid production,” Mr Langworthy said.

“When the growth of ryegrass slows down in summer or winter, plantain generally performs better, and by including plantain in the mix with ryegrass farmers can improve profitability.”

Plantain typically survives for a duration of three years under grazing, as opposed to ryegrass, which has the ability to renew itself and can last for more than 15 years. Mr Raedts said it was not practical or economical for farmers to renew a paddock every three years to include plantain, and alternative management options were required for farmers to reap the benefits.

Trials were established in existing irrigated ryegrass paddocks after spraying for broad leaf weeds during Spring last year. The research team followed-up with observations during the season and dry matter cuts at the end of Summer.

Mr Raedts said it was a challenging season due to army worms eating some of the seedlings and delayed germination of some of the seed due to dry weather, but the outcome was positive.

“The results show that direct drilling is a slightly more effective method than broadcast sowing, as it guarantees contact between the seed and the soil which encourages germination. As a comparison, broadcast sowing is not as successful but is a cheaper option as it doesn’t require specialised machinery,” Mr Raedts said.

“To avoid failure for both methods, paddocks should be treated with slug bait during seeding and against pests like armyworms if they occur after germination.

“The trial showed optimal coverage of uncoated plantain seed in established ryegrass paddocks is approximately 2kg to 4kg per hectare with the direct drilling method, and 2.5kg to 5kg per hectare with the broadcast sowing method. Once you get to 7.5kg per hectare the plantain coverage becomes too dense and starts to compete with the ryegrass which is not ideal.”

Mr Raedts said the research demonstrated that farmers don’t need to start from scratch to incorporate plantain into the mix and can simply top-up existing pastures.

“A target of plantain at 20 to 40 per cent of the dry matter available for the cows to graze, could have financial advantages for dairy farmers,” he said.

The farmers involved in the trial have indicated an interest in retaining plantain in their pastures and are considering topping-up other paddocks.

Findings from this trial will be presented at the Australasian Dairy Science Symposium in New Zealand later this year, and will be shared with industry through extension activities run by TIA’s Dairy Team.

The research is part of the Dairy on PAR project funded by Dairy Australia with in-kind support from TIA. The participating farmers are part of the Dairy on PAR feedbase network, run by the TIA Dairy Team. TIA is a joint venture between the Tasmanian Government and the University of Tasmania.